inject_annotation 1.0.0-alpha.4
inject_annotation: ^1.0.0-alpha.4 copied to clipboard
Compile-time constructor-based dependency injection for Dart and Flutter, similar to Dagger.
import 'package:inject_annotation/inject_annotation.dart';
import 'main.inject.dart' as g;
Future<void> main() async {
/// Create an instance of the [MainComponent] to access the dependency graph.
final mainComponent = g.MainComponent$Component.create();
/// Use the repository to get a greeting for "World".
print(mainComponent.repository.getGreeting(name: 'World'));
}
/// The entry point for accessing the dependency graph.
/// [Component]s declare properties that return an instance of the desired type.
@Component([ApiModule])
abstract class MainComponent {
/// A factory method to create a new instance of [MainComponent].
static const create = g.MainComponent$Component.create;
/// Returns an instance of [Repository] to be used by other classes.
@inject
Repository get repository;
}
/// The [Repository] depends on an instance of [FakeApiClient].
/// Its dependencies are injected via constructor injection.
@inject
class Repository {
/// Creates a new instance of [Repository] with the given [apiClient].
const Repository(this.apiClient);
/// The instance of [FakeApiClient] used by this class.
final FakeApiClient apiClient;
/// Returns a [Future] containing a greeting message for the given name.
Future<String> getGreeting({required String name}) => apiClient.getGreeting(name: name);
}
/// A [module] declares how to get an instance of a particular type.
/// Modules are necessary for 3rd party libraries where the [inject] annotation cannot be used.
@module
class ApiModule {
/// Returns a new instance of [FakeApiClient] to be injected into other classes.
@provides
@singleton
FakeApiClient apiClient() => FakeApiClient();
}
/// A fake API client that returns a greeting message for a given name.
/// In a real implementation, this would typically be a client from a library like Chopper.
class FakeApiClient {
/// Returns a [Future] containing a greeting message for the given name.
Future<String> getGreeting({required String name}) => Future.value('Hello $name!');
}